<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        nav > a {
            position: relative; display: inline-block; padding: .3em 1em 0;
        }
        nav > a::before { content: '';
            position: absolute;
            top: 0; right: 0; bottom: 0; left: 0; z-index: -1;
            background: #ccc;
            background-image: linear-gradient(
                    hsla(0,0%,100%,.6),
                    hsla(0,0%,100%,0)); border: 1px solid rgba(0,0,0,.4);
            border-bottom: none;
            border-radius: .5em .5em 0 0;
            box-shadow: 0 .15em white inset;
            transform: perspective(.5em) rotateX(5deg); transform-origin: bottom left;
        }
    </style>
</head>
<body>
<nav>
    <a href="">Home</a>
    <a href="">Projects</a>
    <a href="">About</a>
</nav>
</body>
</html>